In U.S. Pat. No. 1,161,556 there is described a vertical photomicrographic camera system in which the image from the microscope is projected vertically upward to the photographic film which is located at the top of a telescoping, light tight box. This patent discloses structure connecting the microscope to the photographic plate holder with a bellows and holding the camera aloft by means of adjustable rod stands. Also disclosed is structure for housing this camera in a physician's desk. To operate this camera, the observer looks down on the top of the ground glass screen upon which the image from the microscope is projected, while he reaches down to adjust the focus control of the microscope. Because of this, the projection distance is essentially limited to the length of the human arm, and therefore film formats larger than 4".times.5" could not be conveniently used with this device.
In U.S. Pat. No. 2,077,809 is described a camera mounted on a vertical stand and connected to a microscope by means of a bellows. This device physically resembles a reflex camera, but it is nonfunctional as described and illustrated. As described in the claims there is "a horizontal negative holder on said camera upon which the picture taken by the camera of the object under observation by the microscope is directly reflected to display same to an observer simultaneously with the developing of the picture in the camera." If the microscope image falls upon an opaque plate as claimed so that the observer can see it, then the image will not reach the film to expose it. As we are not told to remove the plate prior to exposure, and as there is no means shown for tilting it out of the beam or sliding it out of the camera, the camera will not function as described. This patent also describes a drawing apparatus which employs a mirror to reflect the light to a drawing plane, the beam of light being received from the tube of the microscope which has been "laterally swung" for the purpose of making drawings of the object. However, this tube is now at a sharp angle with respect to the microscope optical axis. Light received by the microscope objective will not enter this tube, unless special reflecting optics are included in the body of the microscope. Since no such optical elements are shown or described in this patent, it must be concluded that this aspect of the invention is also incapable of operating as described.
In U.S. Pat. No. 2,351,753, Flint et al. describe a vertical photomicrographic camera with a bellows connecting the microscope to the camera head. Height of the camera head is adjustable by means of rack and pinion method and a counterbalance system is provided to offset the weight of the camera. The camera head is provided with a pivotable mirror, which can reflect the image to a ground glass screen at the front to be used for focussing, and then pivoted out of the optical beam as the film is exposed. A hood is provided around the ground glass screen to cut down on the undesirable effects of overhead lighting during focussing. The concepts and methods set forht in this patent have dominated the field of large format photomicrography for the past four decades. These same methods are employed in the recently marketed Kenro MP 812 photomicrographic camera system. This is an 8".times.10" camera system which is capable of providing images on the recently released 8".times.10" Polaroid.RTM. Print Film and Transparency material. This camera also consists of a large vertical stand which holds the camera head above the microscope. Focussing is accomplished by means of deviating the image to a large ground glass screen which is partially shielded from room lights by a hood. The camera head is connected to the microscope by means of a bellows system. This is indeed a large format photomicrographic camera system based upon the art and structure of the Flint et al. patent. Reflex cameras of slightly smaller format (e.g. 4".times.5") have also been coupled to microscopes by means of solid, plastic or metal, conical tubes that serve both as the structural support for the camera, and also as the light tight bellows. Devices such as this are currently available as photomicrographic cameras for the Olympus.RTM., Nikon.RTM., and other microscope systems. These devices are also provided with reflex view focussing means. Other devices are available that allow a worker to connect a single lens reflex camera (such as a modern 35 mm camera) to the microscope. Some of these, such as the Nikon.RTM. F adapter, were designed with the correct realization of the importance of a small, positive correcting lens when the microscope image must be focussed at a very short (4"-6") projection distance. Others are now marketed without a correcting lens, and the worker achieves focus by focussing the microscope, which results in the objective lens being significantly away from the position at which it was designed to operate. This results in degradation of the quality of the resultant picture. These adapters simply constitute light tight tubes that link the 35 mm camera to the microscope and support it above the microscope with the film plane centered on the optical axis of the microscope. Focussing is accomplished by looking in the camera reflex view port. In the case of the Nikon.RTM. system, a specially configured ground glass screen may be mounted in the camera to facilitate focussing at low light levels as is encountered at high magnifications and in dark field photomicroscopy.
It is therefore an object of the present invention to provide a new and improved method and means of producing large format photomicrographs from conventional optical microscopes.